Lubricant



Patented F ch. 7, 1939 UNITED STATES PATENT OFFICE Atlantic RefiningCompany, Philadelphia, Pa., a. corporation of Pennsylvania.

No Drawing. Application June 9, 1936, Serial No. 84,295

6 Claims. (01. 87-9) The present invention relates to the art oflubrication, and more particularly to the lubrication of surfacesengaging under extreme pressure, as for example, the rubbing surfaces ofhypoid gears, free wheeling transmissions, speed reducers and the like.

The general tendency in the design of modern machinery has been toward ahigher ratio between power and dead weight.

ally true in the automotive industry, and in recent years certain typesof gears and other mechanisms have been developed with the operatingpressures on the working surfaces so high that ordinary mineral oillubricants will not provide sufiicient lubrication for satisfactoryoperation.

Heretofore it has been thought that lubrication consists in maintaininga film of oil between the rubbing surfaces, thereby preventing them fromcoming into contact with one another and thus preventing wear. That thiscondition exists in well lubricated bearings is well known, but thisconception of lubrication does not apply-to highly loaded gears. In welllubricated bearings the loads rarely exceed 2000 lbs. per sq. in.projected area and the rubbing speeds are generally high enoughtomaintain a film of oil which separates 'the rubbing surfaces. Inautomobile gears, the pressures between gear teeth reach very highvalues and even the most viscous oils or greases cannot be retainedbetween the surfaces of the teeth in a sufliciently thick film toprevent metal to metal contact, particularly when operating temperaturesof 210 F. or higher are commonly encountered.

It has been known that compounded lubricants such as, for example,mineral oils containing fatty oils, fatty acids, metallic soaps, sulfuror combined chlorine, possess lubricating qualities 40 which render themsuitable for use under high operating pressures. These compounded oilsfunction satisfactorily under conditions which would cause failure of anunblended mineral oil, if used alone. It is believed that the successful5 use of such compounded oils depends upon the adsorption and reactionor union of certain components of these oils with the metal surfaceswhereby a film of metallic compound, such as, for example, iron sulfideor chloride is formed. 50 It appears that such a film or plating has alow This is especicoeflicient of friction and that satisfactoryoperation of heavily loaded bearings or gears depends upon the formationand maintenance of such a film, and not upon the retaining of a film ofoil between the bearing surfaces. The hydro- 5 carbon oil constituent ofan extreme pressure lubricant serves primarily to remove frictionalheat, to wash away any solid particles which may result from wear, andto prevent oxidation of the engaging surfaces. 10 I have discovered thatorganic compounds of phosphorus and nitrogen, and more particularly thecompounds which may be termed, in general, the substituted amides of thephosphorus acids, when admixed with hydrocarbon oils, are of specialutility in the field of extreme pressure lubrication. These compoundsmay be prepared, in accordance with my invention, by the reaction ofhalogen and/or sulfur derivatives of phosphorus with primary andsecondary amino compounds. More particularly, one or more compounds fromthe group phosphorus trichloride PCla; phosphorus pentachloride PCls;phosphorus oxychloride POCla; phosphorus sulfochloride PSCla; and thephosphorus sulfides Pass and P285 .may be reacted with a primary orsecondary amino compound to yield products which may be described as thesubstituted amides of the phosphorus acids.

The amino compounds'which I may employ in the preparation of my reactionproducts comprehend one or a mixture of any of the primary and secondaryaliphatic, aromatic, hydroaromatq- 10 and heterocyclic amines. The.aliphatic amines include, for example, monoand dimethyl'amine and theirhomologues, ethyl-, propyl-, butylamines and the like, as well as thehalogen substituted aliphatic amines, for example, chloro-butylamine andchloro-amylamine. matic amino compounds may be represented, for example,by aniline, toluidine, xylidine, phenylene diamine, naphthylamine,anthramine, benzylamine, methylamline and the like. The hydroaromaticamino compounds include cyclohexyl- 45 amine, tetrahydro-naphthylamine,methylcyclohexylamine and the like. The heterocyclic amino compounds maybe represented, for example, by furfurylamine,-piperidine,tetrahydroquinoline, aminopyrldine and the like. Other 50 Thearosubstituted ammonias containing at least one reactive hydrogen atom,such as phenylhydrazine, may be suitably employed. In general. theprimary and secondary amino compounds contemplated have the followingformulae:

R RNH: and NH wherein R and R are of the group consisting of aliphatic,aromatic, hydroaromatic and heterocyclic radicals, and the substitutionproducts thereof.

Herein, the term reaction product is to be understood to comprehend thecompounds formed by the reaction of the halogen and sulfur derivativesof phosphorus with primary and secondary amino compounds.

In preparing my lubricant, I add to a suitable mineral oil one or amixture of two or more of my reaction products in quantity sufficient toimprove the value of the oil as a lubricant to any desired extent,depending upon the operating conditions under which the lubricant is tobe used. I have found that the quantity of reaction product required, ingeneral, does not exceed substantially 5% by weight of my composition.Quantities as small as 3%, or even 1% or less, have been found toimprove lubricating oils to a satisfactory extent. In certain instances,0.1% to 0.5% by weight of the reaction product was sufficient to improvethe lubricating oil to the desired extent. In preparing my lubricant, Imay obtain a homogeneous solution or stable suspension of my reactionproduct in mineral oil by agitating the mixture at normal or elevatedtemperatures, or I may dissolve the reaction product in a suitablesolvent and add the resulting solution to the oil, thereafter removingthe solvent by vaporization.

The mechanism by which the reaction prodnets in lubricating oilsfunction to improve the sorption of the compounds upon the metalsurfaces of the bearings or other lubricated parts, and the reaction orchemical combination of such compounds with the metal under theinfluence of localized high temperature and pressure to form a coatingor plating having a low coeillcient of friction which is resistant toseizure under high operating pressures.

The following tables indicate some of the reaction products obtained bythe treatment of primary and secondary amines with the phosphorushalides. The treatment may be carried on in the presence of hydroxyand/or mercaptan compounds, whereby other groups are introduced into thereaction products. Or, the initial reaction products may subsequently bereacted with a hydroxy and/or mercaptan compound. The resultingproducts, more complex in structure, have been found suitable for use asaddition agents for hydrocarbon oils. In the formulae given in tables,R, and R. may be the same or different aliphatic, aromatic,hydroaromatic and heterocyclic radicals, while X" represents halogen, i.e., chlorine, bromine or fluorine. The reaction product may be one or amixture of compounds, depending upon the ratio of the reactingcomponents, the time and temperature of the reaction, and thecompleteness of the reaction between the components. The hydroxy and/ormercaptan compounds which may be employed in the reaction include, forexample, methyl alcohol and mercaptan and their homologues; phenol andphenyl mercaptan and their homologues; cyclohexanol and cyclohexylmercaptan and their homologues; and various heterocyclic compounds suchas furfuryl alcohol, furfuryl mercaptan, hydroxyquinoline and pyridyl-mercaptan.

Table 1 Reaction components Reaction products RNH BNH RNHri-PX; annex,rx RNH P RNH RNH X 0B BNH RNH:+PXa+B/0H RNHP/ BNHP r-oa' on on BNH x as"BNH RNH:+PX:+RSH lannr RNHP/ P-SR' an an RNH RzN BzN R|NH+PX| RaNPX: \PXRsN P Rm Rm x 011' RzN R1NH+PX:+R0H mNP RNP \POR OR or. RaN

X en mN amu+rxl+wsn RaNP RINP P-SR' an an am manner, a number ofreaction products which may be suitably employed as addition agents forlubricants.

Table 4 Hexabutyl phosphorous acid amide [(Ce a 1 ]a Tris-cyclopentaethylene phosphorous acid amide 1 8 Isobutg aminephosfihonic acidchloride H;) CHCH2 HPQCI Isobutglammgphosghomc acid anilide a) C CH,HP0( o s)2 Isobut lam ingihoighonic acid fiheglhydrazide a a HPO(NHN a)2 Benzziamme hosphonic acid chloride CHEM-IP00], Diphen l benz laminehos honate CH.NEIPO (OEJI;

Hexaethyl phNoixpll ioric acid amide 2 2 3 'n-Pug) laminethiophosphonieacid chloridev gl NHPsCl Diethyl n-propylaminethiophosphonate C3H'INHPS(O z a 2 n-Pngpyiaminethlofihosfphomc acid amlide gHqNHPSSN C N,N',1(I:"-trietl;ypghiophosphoric acid amide S 3 Diprop laminethiophosphonicacid chloride (cgHfl NPSCi Piperdinethiophosphinic acid chloride C H NPSCI HexaetIyI thigphosphoric acid amide I 2 5 2 n-Pro glaminephossinicacid chloride ,H-,NH),PO l

Phcn 1 benzylaminelphos hinate oBa a a) Table 4-Continued-Diisobuti'lnminephosphonic lacid chloride C1 Chlor821riilinepllosphonicacid chloride CIC H NHPOCL;

Typical examples of my improved lubricants and methods of preparing thesame are as follows:

Example 1 0.1 mole of phosphorus oxychioride, POCla, in ether solutionwas added to 0.7 mole of mono-nbutylamine in ether solution withstirring. The mixture was refluxed on a steam bath for about 3 hours,removed and cooled, and thenwashed with dilute HCl solution and finallywith water. The ether solution of the reaction product, N, N,N"-tri-n-butyi phosphoric acid amide, was dried over anhydrous K2CO3,the ether then removed by distillation and the reaction product, in theamount of about 1% by weight, was added to a hydrocarbon oil having aSaybolt universal viscosity of 304 seconds at 100 F. and an A. P. I.gravity of 29.5. This blended oil, when tested in an Almen extremepressure lubricant testing machine at 200 R. P. M., withstood a pressureof 17,000 lbs/sq. in. projected bearing area before failure, whereas theunblended hydrocarbon oil failed at a pressure of only 4,000 lbs/sq. in.projected bearing area.

Example 2 0.1 mole of phosphorus oxychloride, POCla, in ether solutionwas added to 0.6 mole of di-nbutylamine in ether solution with stirring.The

mixture was refluxed on a steam bath for about 2 hours, and 0.6 mole ofmono-n-butylamine was added. The refluxing was continued for abouthours, the mixture then removed and cooled, and washed with water. Theether solution of the reaction product, poly-butylphosphoric acid amide,was dried over anhydrous KzCOa, the ether evaporated off and the excessunreacted amine removed from the product by distillation under reducedpressure. The reaction product, in the amount of about 1% by weight wasadded to the hydrocarbon oil mentioned in Example 1 and the blended oil,when tested under the conditions set forth in Example 1, withstood apressure of 15,000 lbs./sq.. in. projected bearing area before failure,whereas the unblended hydrocarbon oil failed at a pressure of 4,000lbs/sq. in. projected bearing area.

Example 3 0.04 mole of phosphorus oxychloride, POCla, in benzenesolution was added to 0.25 mole of di-nbutylamine in ether. solutionwith stirring. The mixture was refluxed on a steam bath for about hours,removed and cooled, and washed with water. The ether solution of thereaction product, di-n-butylamine-phosphonic acid chloride, was driedover anhydrous K2003, the ether evaporated off and the excess unreactedamine removed from the product by distillation under reduced pressure.The reaction product, in the amount of about 2% by weight, was added tothe hydrocarbon oil mentioned in Example 1 and the blended oil, whentested under the conditions set forth in Example 1, withstood a pressureof 16,000

lbs/sq. in. projected bearing area before failure,

whereas the unblended hydrocarbon oil failed at a pressure of 4,000lbs./sq. in. projected bearing area.

Example 4 0.07 mole of phosphorus sulfochloride, PSCla, in naphthasolution was added to 0.05 mole of mono- .n-butylamine in naphthasolution with stirring.

The mixture was refluxed on a steam bath for about 11 hours, removed andcooled, filtered and the filtrate washed with water. The naphthasolution of the reaction product, N, N, N"-tr1-nbutyl phosphoric acidamide, was heated to a temperature sumcient to distill off the naphtha.The reaction product, in the amount of about 1% by weight was added tothe hydrocarbon oil mentioned in Example 1 and the blended oil, whentested under the conditions set forth in Example 1, withstood a pressureof 17,000 lbs/sq. in. projected bearing area before failure, whereas theunblended hydrocarbon oil failed at a pressure of 4,000 lbs/sq. in.projected bearing area.

Example 5 0.1 mole of phosphorus sulfochloride, PSCla, was added to 0.2mole of di-n-butylamine with stirring. The mixture was refluxed by meansof an oil bath at a temperature of about 240 F. to 265 F. for about 3hours, and thereafter was steam-distilled to produce a distillate and aresidue. The distillate was extracted with ether and the ether extractwas then heated to an elevated temperature in order to drive off theether. The reaction product, di-n-butylamine-thiophosv phonic acidchloride in the amount of about 1% by Weight was added to thehydrocarbon oil mentioned in Example 1 and the blended oil, when testedunder the conditions set forth in Example 1, withstood a pressure of22,000 lbs/sq. in. projected bearing area before failure, whereas theunblended hydrocarbon oil failed at a pressure of 4,000 lbs/sq. in.projected bearing area.

Example 6' 0.03 mole of phosphorus trichloride, PCla, in naphthasolution was added to 0.25 mole of din-butylamine in naphtha solutionwith stirring. The mixture was stirred at room temperature for about 2hours, then filtered, and the filtrate Washed with water. The naphthasolution of the reaction. product, hexa-n-butyl phosphorus acid amide,was dried over anhydrous K2CO3, the naphtha evaporated oil and theexcess unreacted amine removed from the product by distillationunderreduced pressure. The reaction product, in the amount of about 1%by weight was added to the hydrocarbon oil mentioned in Example 1 andthe blended oil, when tested under the conditions set forth in Example1, withstood a pressure of 22,000 lbs/sq. in. projected bearing areabefore failure, whereas the unblended hydrocarbon oil failed at apressure of 4,000 lbs/sq. in. projected bearing area.

It will be seen, from the above examples, that the addition of myreaction products to a hydrocarbon oil improves the lubricating value ofsuch an oil to a marked degree, and imparts to the oil certainproperties which render it suitable substitution products thereof, arerepresentative examples of this type of materials.

In another aspect of my invention, I have found that these reactionproducts not only improve the load-bearing capacity of hydrocarbon oilsbut also impart thereto a marked resistivity to oxidation and sludgeformation. For example, a lubricating oil containing about 1% by weightof N, N, N"-tri-n-butyl phosphoric acid amide, when subjected to anoxidation test at 340 F. for 96 hours, developed only 18 milligrams ofsludge per gram of oil, whereas the unblended lubricating oil, under thesame test, produced 40 milligrams of sludge per gram bf oil.

Furthermore, the addition of my reaction products to lubricating oils,especially the highly parafllnic oils produced by solvent extractionprocesses, inhibits and in many cases prevents, the corrosion ofcopper-silver-cadmium and copperlead bearings of internal combustionengines lubricated with such oils.

While I have described my invention with reference to the lubrication ofgears and bearings operating under heavy loads, I do not intend to limitmyself thereto, but contemplate the use of my lubricant in operationssuch as the cutting and boring of metals, in which conditions of extremepressure and temperature are normally encountered, and also in thelubrication of mechanisms operating under moderate pressures, as forexample, the crankcase bearings and cylinder walls of internalcombustion engines. Furthermore, my compounded oil may be utilized as abase in the preparation of thickened oils, 1. e., greases, by theaddition thereto of soaps or other conventional thickening agents, inorder to obtain lubricants of desired viscosity. My compounded oil mayalso be blended with fatty oils, fatty acids, synthetic esters andthe'like, or the reaction products, per se, may be admixed with fattyoils, for the lubrication of mechanisms in which the presence of a fattyoil is desirable.

What I claim is:

1. A lubricant comprising a hydrocarbon oil and a small proportion of aproduct of reaction of at least one compound from the group PCls, P0013,P8013, P283 and P285 with an aliphatic amine having at least onehydrogen atom directly connected to the nitrogen atom.

2. A lubricant comprising a hydrocarbon oil and a small proportion of aproduct of reaction of at least one compound from the group PC15,

P0013, P SC13, P283 and PzSs with a butylamine having at least onehydrogen atom directly connected to the nitrogen atom.

3. A lubricating oil composition comprising a relatively largeproportion of a lubricating oil of the type which normally tends torupture at the surface of contact with a bearing-metal under relativelyhigh bearing pressure, and in in-'- timate homogeneous combinationtherewith a small but sufilcient proportion of the oil-miscible,substantially water-insoluble condensation reaction product ofphosphorus trichloride and an aryl amine having at least one hydrogenatom attached directly to the nitrogen atom to impart extreme pressurelubricating characteristics to said oil.

4. A lubricant comprising a hydrocarbon oil and a small proportion of aproduct of reactionof at least one compound from the group PCls,

POCla, PSCla, P283 and PzSs with an amine having at least one hydrogenatom directly connected to the nitrogen atom.

5. A lubricant comprising a hydrocarbon oil and a small proportion of aproduct of reaction of at least one compound from the group PCl5, POCla,PSCls, P233 and P235 with an aromatic amine having at least one hydrogenatom directly connected to the nitrogen atom.

6. A lubricant comprising hydrocarbonoil and a small proportion of aproduct of reaction of at least one compound from the group F615, P0013,P8013, 22S: and P285 with an amine having at least one hydrogen atomdirectly connected to the nitrogen atom and with a compound from thegroup consisting of hydroxy and mercaptan compounds. 5

DAVID mm.

